Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
  • C07C209/24—Preparation of compounds containing amino groups bound to a carbon skeleton by reductive alkylation of ammonia, amines or compounds having groups reducible to amino groups, with carbonyl compounds
  • C07C209/26—Preparation of compounds containing amino groups bound to a carbon skeleton by reductive alkylation of ammonia, amines or compounds having groups reducible to amino groups, with carbonyl compounds by reduction with hydrogen

Definitions

• N-methylbutylamine is prepared by feeding continuously butanal into an aqueous or a hydroalcoholic sodium hydroxide solution in a hydrogen atmosphere and at a temperature in the range between about 20 and 200 C.
• the solution contains about 0.25 to 5 moles of monomethylamine per mole of water and a catalytic amount of a hydrogenating catalyst.
• This invention relates to a process for manufacturing N-methylbutylamine.
• N-methylbutylamine can be prepared by reacting monomethylamine, butanal and hydrogen in the presence of a hydrogenating catalyst in accordance with the following reaction:
• the carbonyl compound and the primary amine are introduced into an autoclave wherein the resultant mixture is subjected to a catalytic hydrogenation under a temperature and a pressure which allows the reaction to proceed at a sufficiently high rate.
• the reaction may take place either with or without a solvent. Using this technique, the yields are generally poor.
• Th low yields of this process may be contributed by the formation of side-products because aldehydes and ketones, especially aldehydes, have a strong tendency to undergo self-condensation to form undesirable side-products in the presence of strongly basic compounds such as the primary amine.
• the butanal in manufacturing N-methbutylamine, the butanal can be caused to form Z-ethyl-l-hexanal or Z-ethyl-l-hexanol according to the following equations:
• the carbonyl side-products produced by the condensations of the aldehydes or the ketones at the beginning stage of the reaction may in turn react with the primary amine to form secondary amines.
• the Z-ethyl-lhexanal produced according to one of the equations stated hereinabove may react with momomethylamine and hydrogen to produce 1-methylamine-2-ethylhexane according to the following reaction:
• the aldehydes and the ketones will also react with secondary amines to produce tertiary amines.
• secondary amine a secondary amine
• N-mehylbutylamine there is still another side reaction of significance which involves the reaction of the aldehyde and a secondary amine, dimethylamine.
• the latter is an impurity in amounts of the order of 0.5% by weight in commercial grade monomethylamine used as a starting material for the manufacture of N-methylbutylamine.
• the reaction for the formation of the tertiary amine, N-dimethylbutylamine may be represented by the following equation:
• N-dimethylbutylamine has adverse affects on the quality of N-methylbutylamine and cannot be separated from the latter readily because the difference in the boiling points of the two compounds at atmospheric pressure is small, i.e. 93 C. and 91 C. respectively.
• the invention comprises feeding gradually butanal into an aqueous or a hydroalcoholic sodium hydroxide solution in a hydrogen atmosphere and at a temperature in the range between about 20 C. and 200 C.
• the solution contains about 0.25 to 5 moles of momomethylamine per mole of water and a catalytic amount of a hydrogenating catalyst.
• the N-methylbutylamine thus produced is then recovered from the reaction medium.
• the reaction may be carried out in the aqueous or hydroalcoholic sodium hydroxide solution of any concentration. I found that yields are better if the amount of sodium hydroxide in the solution is between 0.1% and by weight. The best results are usually obtained using a concentration of 1% to 3% by weight of sodium hydroxide solution.
• the molar ratio of water to monomethylamine is maintained, as stated hereinabove, generally in the range between 0.25 and 5. However, it is preferred that the ratio be in the range between 1 and 2.
• the amount of butanal to be used in the reaction may vary within a wide range. It is generally preferred that not more than the stoichiometric amount be used. I found a molar ratio of monomethylamine to butanal in the range of 1 and 1.5 to be eminently suitable and an optimum ratio in the vicinity of 1.1.
• the butanal is to be fed into the reaction medium gradually and preferably continuously so the stationary concentration of butanal in the reaction medium is relatively low.
• the rate is governed generally by the reaction conditions and particularly by the reaction rate. It should not be so high as to cause large accumulations of butanal nor so low as to increase unduly the reaction time.
• the reaction may be carried out in a wide temperature range of to 200 C. It is preferred, however, that the reaction temperature be in the neighborhood of about 100 C.
• the hydrogen pressure maintained in the reaction vessel, such as an autoclave can also be varied within a wide range of 1 to 100 bars, however pressure in the vicinity of 30 bars is preferred.
• the hydrogenation may be effected with any suitable catalyst.
• a large number of such catalysts are known. I found Raney nickel, whose catalytic activity and durability in an alkaline medium are exceptionally good, to be particularly suitable.
• N-methylbutylamine covers all the isomers.
• EXAMPLE I In this example, a small quantity of sodium hydroxide was employed. The following materials were introduced into a horizontal autoclave of stainless steel having a capacity of 5 cubic decirneters, the autoclave being provided with a reciprocating mixing device moving in a direction perpendicular to the axis of the autoclave:
• a process according to claim 2 wherein the amount of monomethylamine in the solution is about 1 to 2 moles per mole of water in the solution.
• a process for manufacturing N-methylbutylamine which comprises feeding continuously not more than a stoichiometric amount of butanal into a 1% to 3% by weight of aqueous or hydroalcoholic sodium hydroxide solution in a superatmospheric hydrogen atmosphere and at a temperature in the range between C. and 200 C., said solution containing about 1 and 2 moles of monomethyl-amine per mole of water and a catalytic amount of hydrogenating catalyst, and recovering the N-methylbutylamine therefrom.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

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• 1966
  • 1966-03-31 FR FR55755A patent/FR1492863A/fr not_active Expired
• 1967
  • 1967-02-28 BE BE694749D patent/BE694749A/xx not_active IP Right Cessation
  • 1967-03-16 DE DE1618018A patent/DE1618018C3/de not_active Expired
  • 1967-03-23 LU LU53270D patent/LU53270A1/xx unknown
  • 1967-03-27 US US625977A patent/US3442951A/en not_active Expired - Lifetime
  • 1967-03-29 GB GB14329/67A patent/GB1116610A/en not_active Expired
  • 1967-03-30 NL NL676704542A patent/NL154721B/xx not_active IP Right Cessation

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